What does the KEEP statement do in a SAS program?

The KEEP statement in SAS serves the purpose of retaining specific variables in a dataset while excluding all others. When you use the KEEP statement, you list the variables you want to keep, and any variable not mentioned in the statement will be dropped from the resulting dataset. This is particularly useful when working with large datasets where you may only need a subset of the available variables for further analysis or processing.

The direct application of the KEEP statement ensures that your final dataset is streamlined to include only the data that is relevant to your work, enhancing efficiency and clarity. This selective approach helps to reduce clutter and makes it easier to focus on the essential variables.

The other choices do not accurately describe the functionality of the KEEP statement. The option related to dropping variables describes the DROP statement, while the notion that it only applies to character variables is incorrect because the KEEP statement works for both character and numeric variables. The mention of controlling the input format is unrelated, as the KEEP statement focuses solely on variable retention without addressing their formats.